The present invention relates to a data storage tape cartridge. More particularly, it relates to a tape reel portion of a data storage tape cartridge.
Data storage tape cartridges have been used for decades in the computer, audio and video fields. While other forms of media storage, such as disk cartridges, are also available, the data storage tape cartridge continues to be an extremely popular form of recording large volumes of information for subsequent retrieval and use.
The data storage tape cartridge generally consists of an outer shell or housing maintaining at least one tape reel and a length of magnetic storage tape. The storage tape is wrapped around a hub portion of the tape reel and is driven through a defined tape path by a driving system. The housing normally includes a separate cover and a base, the combination of which creates an opening (or window) of some type for allowing access to the storage tape by a read/write head upon inserting the data storage tape cartridge into a tape drive. This interaction between storage tape and head may take place within the housing (for example, a mid tape load design), or the storage tape may be directed away from the housing to an adjacent area at which the read/write head is located (for example, a helical drive design or a leader block design). Where the tape cartridge/drive system is designed to direct the storage tape away from the housing, a single tape reel configuration is normally employed. Conversely, where the tape cartridge/drive system is designed to provide head-storage tape interaction within or very near the housing, a two-tape reel configuration is typically utilized.
Regardless of the number of tape reels associated with a particular data storage tape cartridge, assembly of the tape reel within the housing is relatively similar. As a starting point, the tape reel normally includes a hub and opposing flanges. The flanges are disposed at opposite ends of the hub, and are spaced to approximate a height of the storage tape. Once assembled, the tape reel is then disposed within the housing. One common construction method is to first secure a hub pin to a portion of the housing, for example, the cover. More particularly, the hub pin is positioned to extend in a generally perpendicular fashion from an interior surface of the cover. The tape reel is then placed over the hub pin. In this regard, an axial bore is normally formed in the hub. The axial bore has a diameter slightly greater than a diameter of the hub pin such that the hub, and thus the tape reel, is free to rotate about the hub pin. During use, a portion of the tape drive engages a portion of the hub, via an opening in the base, and rotates the hub and thus the tape reel. For example, an exterior surface of the tape reel may include teeth which are sized to be engaged by a reciprocally toothed portion of the tape drive.
While allowing for rotation of the tape reel during use is an obvious necessity, it is equally important that the tape reel remain relatively stationary when the data storage tape cartridge is not in use. If the tape reel is allowed to freely rotate when not otherwise engaged by the tape drive, the storage tape may become loose within the housing. This is a highly undesirable situation in that the storage tape may be permanently displaced from the desired tape path, crease or otherwise become damaged. Under these circumstances, data may be lost or the data storage tape cartridge rendered unusable.
In light of the above concern, data storage tape cartridges are currently designed to include a locking mechanism or brake with the tape reel. When the data storage tape cartridge is not in use, the locking mechanism prevents the tape reel from rotating about the hub pin. During use, however, the locking mechanism is disengaged such that the tape reel can be rotated by the tape drive. One common type of locking mechanism includes a compression spring associated with the tape reel. When the data storage tape cartridge is not being used, the compression spring biases a portion of the tape reel into engagement with the base. In this engaged position, the tape reel is effectively "locked" to the base. During use, a chuck portion of the tape drive presses against the tape reel with a force sufficient to overcome the bias of the compression spring. As a result, the tape drive moves the locking mechanism away from engagement with the base such that the tape reel is free to rotate.
While the above-described braking mechanism does address the problem of undesired tape reel rotation during periods of non-use, other concerns still remain. In conjunction with advancements in tape drive and read/write head technology, various improvements in the data storage tape cartridge design have greatly enhanced performance capabilities. For example, evolution of magnetic tape media has resulted in storage tapes with increased storage capability and product longevity. Similarly, improvements in read/write head technology has resulted in the ability to read and write larger volumes of information on increasingly smaller tracks defined along the height of the storage tape. While these efforts are clearly beneficial, greater demands are placed on the data storage tape cartridge design. For example, with the use of smaller information tracks, the data storage tape cartridge must be configured to maintain the desired tape path within an extremely tight tolerance range. Any slight deviation in the desired tape path may result in reading/writing errors.
There are several possible causes of tape path deviation following construction of the data storage tape cartridge. One common type occurs where the hub pin is forced out of the preferred perpendicular relationship with the cover. For example, when a user accidentally drops the data storage tape cartridge, the resulting impact may cause a deflection in the hub pin. While obviously not advised, accidental dropping or other unexpected impacts on the data storage tape cartridge can and will occur. When the hub pin is forced to a different orientation relative to the cover, the tape reel, otherwise disposed about the hub pin, likewise changes its position. Consequently, the tape path generated by the position of the tape reel within the housing will change. Even a slight change in the angular position of the tape reel may result in reading and writing errors.
Data storage tape cartridges are important tools used to maintain vast amounts of information. However, with increasing complex reading/writing and magnetic tape technology, design of the data storage tape cartridge must evolve to prevent deflection of the hub pin, and thus any resulting errors, when the data storage tape cartridge is accidentally dropped or otherwise impacted. Therefore, a need exists for a data storage tape cartridge having a tape reel assembly designed to reinforce the hub pin.